An excavator is known as a kind of work machine having a work unit. The work unit of the excavator is driven by a hydraulic cylinder. The hydraulic cylinder is actuated by hydraulic fluid discharged from a hydraulic pump. Patent Literature 1 discloses a hydraulic control device having a merging-separating valve that performs switching between a merged state in which hydraulic fluid discharged from a first hydraulic pump and hydraulic fluid discharged from a second hydraulic pump are merged and a separated state in which these two kinds of hydraulic fluid are not merged. In the separated state, a first hydraulic actuator is actuated by the hydraulic fluid discharged from the first hydraulic pump, and a second hydraulic actuator is actuated by the hydraulic fluid discharged from the second hydraulic pump.